Method of preparing mated embossing rolls



g- 1966 F. w. BRODERICK METHOD OF PREPARING MATED EMBOSSING ROLLS 2Sheets-Sheet 1 Filed Dec. 16, 1964 g- 1966 F. w. BRODERICK METHOD OFPREPARING MATED EMBOSSING ROLLS 2 Sheets-Sheet 2 Filed Dec.

United States Patent 3,268,378 METHOD OF PREPARING MATED EMBOSSING ROLLSFrank W. Broderick, P.O. Box 2, Stirling, NJ. Filed Dec. 16, 1964, Ser.No. 418,732 4 Claims. (Cl. 1S614) This invention relates to a method ofpreparing mated embossing rolls and more particularly to a method andapparatus of cold finishing with cold embossing of a strip of dullfinish aluminum sheet to produce depressed glossy cold finished surfacesadjacent to elevated nonglossy wearing or pitted surfaces.

This invention is a continuation-in-p-art of patent application Ser. No.145,956, filed October 18, 1961, now abandoned.

In the preparation of treads now commonly used in automobiles, theembossed glossy surfaces 'elevated above the original horizontal planeare easily scratched and otherwise disfigured by conventional shoetraffic going in and out of the automobile, thereby presenting treadshaving unsightly scratched embossed designs thereon.

Moreover, the present practice of purchasing highly polished aluminumsheet for preparing treads for automobiles is unsatisfactory in thatsuch polished aluminum sheet is relatively expensive and is easilymarred in transportation and normal handling so as to produce scratchesthereon rendering the sheet a piece of scrap.

It is an object of this invention to prepare a mated pair of embossingrolls adapted to produce an embossed metal sheet or foil having a designthe top wearing surfaces of which are provided with a roughened designpattern or texture.

It is also an object of this invention to provide a method of producingmetal sheet or foil having embossed designs having raised non-glossysurfaces, such as for example pebble grain, satin finish, and the liketype of surfaces.

It is another object to provide a method of converting commercialaluminum sheet having a conventional nonglossy mill finish to a sheet ofglossy finish by contacting the dull surface of the sheet with asuitably highly polished female roll.

In the preparation of aluminum treads for automobile use, the dullaluminum sheet surface is converted into a glossy surface simultaneouslyas the sheet is being embossed into the design cavities of the femaleembossing roll, the bottom surfaces of said cavities being provided withthe desired pebble grain or satin finish.

The method of this invention is illustrated in the accompanying drawingin which;

FIG. 1 is a perspective view of a portion of a photoerigraved femaleroll having a repeated arrow and repeated annulus design,

FIG. 2 is an enlar ed sectio of FIG- 1, g n view taken on line 2 2 FIG.3 is a section view similar to FIG. 2, showin the conventionalpreparation of a male roll having pro tuberances of a height equal tothe depth of the female cavities,

FIG. 4 is a section view of the male roll of FIG. 3 coated with a resistsoluble only in methyl ethyl ketone FIG. 5 is a section view of FIG. 4after a doctor blade has removed the excess resist so as to have theblade contact the top surfaces of the male protuberances,

FIG. 6 is a view similar to FIG. 5 showing the spray droplets of anasphaltum resist soluble in turpentine,

FIG. 7 is a view similar to FIG. 6 with all the resist removed andshowing the etched pebble grain top surfaces on the male protuberances,

FIG. 8 is a view similar to FIG. 7 showing the ap- "ice plication of anacid resist to only the top surfaces of the male protuberances,

FIG. 9 is a section view of the female roll coated with resist and theprepared male roll about to be mated so as to force out excess resistwith metal contact or engagement between the top of the maleprotuberances and the bottom of the female cavities,

FIG. 10 is a section view of the female roll coated with resist andready for acid etching,

FIG. 11 is a section view of a fully prepared female roll having thebottom walls of its cavities acid etched and receiving the design of thepebble grain finish of the top surfaces of the male protuberances,

FIG. 12 is a section view of a portion of a mated pair of a fullyprepared female roll and a fully prepared rnale roll, shown inexaggeration the .001 to .002 clearance between the smooth surfaces ofthe female and male rolls and showing also the simultaneous contact ofthe rough or pebble grain surfaces of the female and male rolls, and

FIG. 13 is a section view of a metal sheet passed through the rolls ofFIG. 12.

In this invention the bottom of the femalecavities of the femaleembossing roll are provided with roughened or pitted, i.e. satin finishor pebble grain surfaces, which surfaces appearing on the embossedaluminum sheet do not show foot tralfic or other scratches.

Turning now to the drawing, a female steel roll 10 is provided with anengraved design either by the conventional mill and die method or by theconventional photoengraving process. The design may be of a veryintricate nature but for purposes of clarity of illustration a repeatedarrow head 11 and a repeated annulus of ring 12 is used herein, whichappear as cavities in the female roll 10 (FIG. 2).

The design of this female roll is then transferred to a male mating roll13 in the conventional manner using an acid resist coating and asuitable metal etching acid.

By way of an example the depth of the female cavities 14 may be .008inch and the height of the male protuberances 15 is also .008 inch. Themale protuberances are then topped with an acid resist such as asphaltumand the root of the protuberances are etched away in such a manner thatthe height of the protuberance is increased to .010 or more thousandsdepending on the pattern which is to be used on the top of theprotuberance. This topping and acid etching procedure is to preventmarring of the polished surface of the female roll in later transfermating ope-rations.

According to the concept of this invention the male roll 13 is removedfrom the transfer machine and is coated with a methyl ethyl ketonesoluble acid resist coating 16. This resist 16 is not soluble inturpentine.

This coating is then scraped with a metal doctor blade to remove as muchexcess resist as possible and the top of the protuberances are furthercleaned by means of an emery block to produce an absolutely smoothsurface (FIG. 5) receptive to various spray or other methods used toproduce an eventual rough surface on the top surfaces of theprotuberances.

The smooth, clean, metallic surfaces of the protuberances (FIG. 5) arethen sprayed with a turpentine soluble asphaltum acid resist 17 to yielda desired pattern and this sprayed surface of male roll 13 (FIG. 6) isrotated in a bath of suitable etching acid to produce the desired etchpattern or suitable depth. The asphaltum resist may be washed off withturpentine leaving behind the methyl ethyl ketone acid resist 16. Thenthe turpentine washed male roll 13 may be given a second asphaltum sprayand the protuberances again etched in acid to give a novel final etchedpattern.

The protuberances 15 of the male roll 13 (FIG. 5) may be givenmechanically applied rough top surfaces, if desired, in lieu of theetched asphaltum prepared surface. Also the spray etched surface may begiven a mechanical roughness thereto.

Clearly, there are many ways of applying various rough surfaces to thetop of the protuberances 15, including brushing on resist in lieu ofspraying and machine engraving to give ultimate pleasing rough wearingsurfaces of a satin finish, swirl finish, emery finish, pebble grain,and other visual effects.

The use of the asphaltum turpentine soluble resist 17 in conjunctionwith the methyl ethyl ketone soluble resist 16 permits a washing off orremoval of the asphaltum resist and repeated application by re-sprayingto give a plurality of varying depths of satin or emery finishes withoutremoval of the background methyl ethyl ketone soluble resist 16.

Where mechanical finishes are applied to the tops of the protuberances15, the roll is placed in a lathe, grinding machine or engraving machineand the tops of the protuberances are ground, turned or engraved to thedesired finish.

After the protuberances have received the final desired pattern 18 theroll 13 is washed free of all resist (FIG. 7).

Next, the top coating of acid resist 16 of the male roll (FIG. 8) isremoved and the roll of increased protuberance height is mated to thefemale roll covered with acid resist, for example, acid resist 16 in thetransfer machine.

The male roll is brought up so that the top surfaces 18 of theprotuberances 15 contact the bottom walls of the female cavitiessqueezing out excess acid resist 16 to expose metal having thecomplementary pattern of the surface 18. The female roll 11} is thenrotated in a conventional etching acid bath and the pattern 18X isetched into the bottom walls of the female cavities (FIG. 10). Theprevious provision of the extra .001 height of the protuberancesprevents contact between the shiny, high polish smooth surfaces of thefemale roll of the original female roll and the male roll 13.

Removal of the resist from the etched roll 10 (FIG. 10) produces thefinal product female roll (FIG. 11).

When the tw-o final product male and female rolls are brought together(FIG. 12) there is a metal to metal mating of the etched top surfaces 18of the protuberances 15 and the bottom surfaces 18X of the correspondingfemale cavities but no metal engagement of the highly polished femalesurfaces of female roll 10 with the male roll 13.

The embossed foil 19 made of aluminum or other metal or of foil on paperlaminate is shown in FIG. 13 showing the wearing surfaces 18X thereon astransferred from the bottom walls of the cavities of the female roll.

This invention is of a generic nature and is not to be limited by themetal used in the embossing rolls, nor to the type of rough wearingpattern transferred by the female roll to the ultimate embossed sheetand it includes 4 all variations obvious to those skilled in the artupon reading this disclosure. Thus, for example, the final productionfemale roll may be buffed to restore or to enhance its polished surfaceto whatever degree is desired without materially harming the pattern inanyway whatsoever.

Iclaim:

1. The process of preparing mated steel embossing rolls to produceembossed aluminum sheet or foil with protuberances having top roughwearing patterned surfaces comprising preparing a matched set of maleand female metal embossing rolls by conventional masking and etchingprocedure; coating the top male protuberances with acid resist; acidetching said coated protuberances to increase the height of saidprotuberances; removing said acid resist from said protuberances;roughening the top surfaces of said protuberances of said male roll witha desired pattern and transferring said rough pattern surfaces from saidtop of said male protuberances to the bottoms of the correspondingfemale cavities of said female roll by acid resist masking and acidetching whereby the pattern of the top protuberant surfaces of the maleroll is transferred to the bottom of the corresponding female cavities.

2. The process of claim 1 wherein the rough pattern of the top surfacesof the protuberances is obtained by mechanical toughening.

3. The process of claim 1 wherein the top surfaces of the protuberancesis obtained by coating said protuberances of increased height withmethyl ethyl'ketone soluble resist; removing excess ketone resist topresent the smooth bare metal top surfaces of said protuberances;spattering said bare metal with turpentine soluble asphalt resist; acidetching said spattered surfaces and removing said asphaltic resist withturpentine to present a rough pattern.

4. The process of claim 3 wherein said rough pattern on said topsurfaces of said protuberances is spattered again with asphalt resist;acid etching said respattered protuberances and removing said asphaltresist with turpentine to give a pattern rough surface.

References Cited by the Examiner UNITED STATES PATENTS 764,082 7/1904Thorpe 156 14 1,329,088 1/1920 Leitner 156-14 1,900,824 3/1933 Lewis161-125 1,974,011 9/1934 Burgess 156-13 XR 2,068,035 1/1937 Meyer161-125 2,339,145 l/1944 Callum 101-32 2,390,618 12/1945 Roehm 101-322,662,002 12/1953 Sunderhauf et al 156-14 ALEXANDER WYMAN, PrimaryExaminer. DAVID KLEIN, JACOB STEINBERG, Examiners. J. A, BELL, AssistantExaminer,

1. THE PROCESS OF PREPARING MATED STEEL EMBOSSING ROLLS TO PRODUCE EMBOSSED ALUMINUM SHEET OR FOIL WITH PROTUBERANCES HAVING TOP ROUGH WEARING PATTERNED SURFACES COMPRISING PREPARING A MATCHED SET OF MALE AND FEMALE METAL EMBOSSING ROLLS BY CONVENTIONAL MASKING AND ETCHING PROCEDURE; COATING THE TOP MALE PROTUBERANCES WITH ACID RESIST; ACID ETCHING SAID COATED PROTUBERANCES TO INCREASE THE HEIGHT OF SAID PROTUBERANCES; REMOVING SAID ACID RESIST FROM SAID PROTUBERANCES; ROUGHENING THE TOP SURFACES OF SAID PROTUBERANCES OF SAID MALE ROLL WITH A 